Actor Harry Dreyfuss is claiming that Kevin Spacey groped him at age 18 — while his father, actor Richard Dreyfuss, was in the room.

In a self-written account published Saturday on Buzzfeed.com, Harry Dreyfuss describes the alleged 2008 incident, when Spacey was directing Richard Dreyfuss in a play at the Old Vic in London.

Harry Dreyfuss says he was inspired by actor Anthony Rapp, who came forward on Sunday to say Spacey made a sexual advance at him when Rapp was 14, and others who have spoken out against Spacey.

Dreyfuss wrote: “It happened one night when the three of us were alone in Kevin’s apartment rehearsing my father’s lines. My father didn’t see, and I didn’t tell him about the incident for many years. Instead, I spent the next nine years telling people the story at parties for laughs."

Richard Dreyfuss told Buzzfeed he was present for the night in question, and he tweeted Saturday: "I love my son @harrydreyfuss more than I could explain with all the words in the world. And I am so incredibly proud of him right now."

Harry Dreyfuss explained that during the script-reading session, Spacey repeatedly placed his hand on Dreyfuss' thigh while his father was focused on the script. Then it proceeded further.

"Over the course of about 20 seconds, centimeter by centimeter, Kevin crawled his hand from my thigh over toward my crotch. My mind went blank. Suddenly, he had completed his journey and now he had all of me in his hand. I stopped reading the script and my eyes went wide," Dreyfuss wrote.

"I don't know how long we sat there like that. It could have been as little as 20 seconds, or it could have been five minutes. It’s the hardest part of the story for me to recall. What I do remember is that, other than being a shy kid who obviously admired Kevin Spacey a lot, I never once gave him a signal that I would want to be with him in that way."

Dreyfuss ended the piece saying, "I hope my story can serve as inspiration to others who may have felt that they couldn’t or shouldn’t speak up until now."